SELECT statements that return at most one row

A single row query retrieves at most one row from the database. A single-row query SELECT statement has an INTO clause following
the select list and before the FROM clause. The INTO clause contains a list of host variables to receive the value for each
select list item. There must be the same number of host variables as there are select list items. The host variables may be
accompanied by indicator variables to indicate NULL results.

When the SELECT statement is executed, the database server retrieves the results and places them in the host variables. If
the query results contain more than one row, the database server returns an error.

If the query results in no rows being selected, a Row Not Found warning is returned. Errors and warnings are returned in the SQLCA structure. See The SQL Communication Area (SQLCA).